Generally if it is somebody that just wants it for their collection, I charge $2.00 a slide and $4.00 for a print.
Of course, if the slide is rare or unusual then the price goes up some.
Companies that want to use my images in brochures, covers, web sites, etc... I still generally let them have the photo for the above prices. Alaska Airlines recently used one of my photos of an AS 737-700 for some of their internal documents which I let them use without charge (they just downloaded the file from here). Generally, if you want money for something like that they'll just ask someone else. I'm not the only person with a slide of an AS 737-700.
For magazines, generally if your photo is used you should get around $10.00. Centerfolds and covers should yield between $50.00 and $100.00 depending on the subject matter.
As far as books are concerned, generally authors do not pay for photos unless it is on the cover or is a rare, hard to find shot. The photo credit you get is usually payment enough. (Think about it, if an author wants to include a photo of a NW DC-10 in their DC-10 book they are writing they have 1000's of images at their disposal....the fact yours was selected is a major compliment.)
If I can think of anything else I'll post it....right now it's time to watch Green Bay lose.
A noble spirit embiggens the smallest man...